(1) Field of the Invention
The present invention relates to a denture occlusal adjustment system in which preparation of dentures in a denture-production process is performed by a dentist or a dental technician and an occlusal adjustment in the process is performed by a special contractor.
(2) Description of Related Art
A denture-production process generally includes the steps of preparing wax dentures using artificial teeth and wax; replacing a plate made of wax with acrylic resin for denture plate by a lost-wax process to prepare pre-occlusal adjustment dentures, and subjecting the pre-occlusal adjustment dentures to an occlusal adjustment.
In the occlusal adjustment step, the pre-occlusal adjustment dentures are attached to an articulator. The acrylic resin for denture plate has a property of slightly contracting when being polymerized (hardened) and, in many cases, causes a small increase in height of occlusion. In order to correct this, it is necessary to perform a correction adjustment of the occlusion once again.
The occlusion state when the dentures are occluded is confirmed. Then, the occlusion surfaces of artificial teeth are adjusted by grinding to allow the artificial teeth to occlude evenly in horizontal direction. An articulating paper, such as 12-micron carbon paper, is placed between the occluded teeth and the contact portions between the teeth are marked by color. If occlusion is poor, dentures particularly the full dentures are not stable.
However, it is not better to properly grind a portion that strongly contact with the opposite portion. It is necessary to grind and adjust the contact portion while a force-exerting direction is considered so that the dentures will be stabilized while being occluded.
Next, occlusion when jaws are moved in the right-and-left and forward-and-backward directions, or when so-called teeth gnashing is performed, is adjusted. By using an articulating paper with color different from the color of the former articulating paper, occlusion is adjusted by grinding while harmonious occlusion of front and back teeth is considered. Although there are various theories about occlusion, occlusion is adjusted by grinding in the style of “full balanced occlusion” where all the teeth can slidably contact with the corresponding teeth even when the jaw are moved in any direction (teach gnashing).
Grinding is performed so that the dentures are stably occluded when the jaw is moved in the left direction or in the right direction. Occlusion when the jaw is moved forward is similarly adjusted by grinding. A micro-order fine work is repeated.
An occlusal adjustment work is a work for grinding an occluded surface. Specifically, the occlusal adjustment work is a work for marking (coloring) contact portions of the upper and lower jaws in the occlusal surface, which is an occluded surface, by using a carbon paper or the like and grinding such portions little by little. In order to do this work correctly, even an expert may take one or two hours for the work.
The articulator reproduces just an average movement of jaws. Therefore, an occlusal adjustment is also based on theoretical average values. However, the occlusal adjustment can be performed within the minimum range in a dental clinic when dentures are actually applied to a patient by correctly adjusting the occlusion to the theoretical average values. Patient's sense on incongruity, pain, or the like can be minimized. This means that an occlusal adjustment is the most important work in the denture-production process.
Conventionally, the preparation of dentures has been performed by teamwork of a dentist and a dental technician. Among the steps of the denture-production process, the occlusal adjustment requires well knowledge and experience. Thus, the occlusal adjustments have been complicated and difficult works even for dentists and dental technicians through a trial and error process.